* Vivek Goyal <[email protected]> [2007-05-08 19:18]:
> On Thu, May 03, 2007 at 12:19:32AM +0200, Bernhard Walle wrote:
> > * Vivek Goyal <[email protected]> [2007-04-30 10:48]:
> > >
> > > handle_edge_irq() already makes sure that desc->action is not null, still
> > > note_interrupt() is receiving desc->action as null, that's strange. On my
> > > system this is happening for irq 4 and /proc/interrupt shows that it is
> > > coming from "serial".
> >
> > Unfortunately, I couldn't reproduce this here. Vivek, do you have time
> > to take a look at this at your site? For the meanwhile, should I
> > create a patch that checks for desc->action in note_interrupt(), too?
>
> I can reproduce this problem only on one machine. I think there is some
> race condition and your code somehow just exposes it.
thanks for finding that out. Could you try/review out the patch below?
As the lock is only aquired when irqfixup == 2 it shouldn't impact
performance of a 'normal' system.
Thanks,
Bernhard
---
kernel/irq/spurious.c | 18 ++++++++++++++----
1 file changed, 14 insertions(+), 4 deletions(-)
--- a/kernel/irq/spurious.c
+++ b/kernel/irq/spurious.c
@@ -145,10 +145,20 @@ void note_interrupt(unsigned int irq, st
}
if (unlikely(irqfixup)) {
- /* Don't punish working computers */
- if ((irqfixup == 2 && ((irq == 0) ||
- (desc->action->flags & IRQF_IRQPOLL))) ||
- action_ret == IRQ_NONE) {
+ int call_misrouted_irq = action_ret == IRQ_NONE;
+
+ if (!call_misrouted_irq && irqfixup == 2) {
+ if (irq == 0)
+ call_misrouted_irq = 1;
+ else {
+ spin_lock(&desc->lock);
+ if (desc->action && (desc->action->flags & IRQF_IRQPOLL))
+ call_misrouted_irq = 1;
+ spin_unlock(&desc->lock);
+ }
+ }
+
+ if (call_misrouted_irq) {
int ok = misrouted_irq(irq);
if (action_ret == IRQ_NONE)
desc->irqs_unhandled -= ok;
-
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